Multiterminal DC Transmission Systems Based on Superconducting Cables Feasibility Study, Modeling, and Control

This paper deals with the appropriate modeling and control strategy of a multiterminal dc transmission (MTDC) system that incorporates high-temperature superconducting (HTS) dc cables. The system is based on voltage source converters for the interconnection of stiff ac grids. An overview of the high voltage direct current power transfer technology along with the possibilities it enables, as well as an introduction to the concept of multiterminal topology are presented. The operation principles of the superconducting technology are described and the control strategy of HTS-based MTDC networks is presented. To validate the performance and the dynamic response of the system under steady state as well as under fault and load change conditions, a typical four-terminal MTDC network in ring topology is developed in MATLAB/Simulink.

I. Introduction

Progress in the technology of superconducting materials by means of modern higher temperature superconductors of lower cost in parallel with the increased power demand, especially within congested urban environments indicate that superconducting components, such as dc cables, can play a significant role [1] . To that end, adoption of superconductors, while taking advantage of the functionalities that state-of-the-art power converters can contribute for dc transmission might lead to HTS-based dc power systems.